Relationship between morphometric attributes and body weight of juvenile turbots Scophthalmus maximus

To study the effect of morphometric attributes on body weight of the turbot Scophthalmus maximus,morphometric measurement was taken on 1120 3-month-old turbots sampled in a local company in Yantai,Shandong of China.The attributes used in this study include body length,total length,body depth,head length,length between snout tip and frontal of gill cleft,tail handle length,tail handle height,body width,and body weight.A correlation coefficient matrix was constructed,in which the body weight was used as the dependent variable and other attributes as independent variables for path analysis.The path coefficients(P_i),determination coefficients(d_i and d_ ij),and correlation index(R2) were calculated,and major morphometric attributes determined.The results showed that all the correlation coefficient between each independent variable and dependent variable(body weight) were significantly different(P0.01).The total length gave a predominant direct effect(0.720) and determinacy on the body weight,it is the key effective factor,whereas body depth and body width exhibited a slight direct effect(0.211,0.094) and significant indirect effect(0.5558,0.4342) on the body weight via total length.The high value of multiple correlation index R2 at 0.911 between morphometric attributes and body weight suggests that the selected attributes are practical.The multiple regression equation relating the body weight was established as y=-6.216+1.294x_1+0.518x_2+1.293x_3,where y is body weight,x_1,x_2,x_3 is the total length,body depth,and body width,respectively.